Andersonita
Andersonita is a mineral with formula Na₂Ca(UO₂)(CO₃)₃·6H₂O, in the Carbonatos group. This specimen comes from Mina Eureka, Castell-estaó, Lleida, Catalunya, España and joined the Terrium collection in 2025.
Description
Crusts of yellow-green andersonite microcrystals on siliceous matrix, with patches of yellow cejkaite; intense blue-green fluorescence under UV. Very low radioactivity, maximum 0.50 µSv/h at short distance.
About Andersonita
NEOFORMATION. A hydrated uranyl-calcium carbonate, highly fluorescent, somewhat light-sensitive and water-soluble. It is the most abundant neoformation mineral in the Eureka mine deposit. In effect, it formed as a mining-induced neoformation in only 40 years, appearing on gallery walls due to human intervention. First record for the country. Under UV light, serpentine bands of near-electric blue appear across the gallery walls.
About the locality
The Eureka mine is a small uraniferous occurrence at Castell-estaó (La Vall Fosca), prospected in the mid-20th century but never brought into production; known for autunite and fluorescent uranyl carbonates such as andersonite.
Technical data
- Catalogue No.
- 0178
- Composition
- Na₂Ca(UO₂)(CO₃)₃·6H₂O
- Name
- Andersonita
- Group
- Carbonatos
- Category
- Núcleus Ardens
- Matrix
- Roca silícea
- Associations
- Cejkaita
- Mine
- Mina Eureka
- District / Municipality
- Castell-estaó
- Province
- Lleida
- Region
- Catalunya
- Country
- España
- Size (cm)
- 8 x 5.5 x 3
- Weight
- 150 g
- Acquired
- 2025
- Etymology
- Named in honour of Charles Alfred Anderson.
- Quality
- Buena
- Value trend
- Estable
Related specimens
- Abellaíta — España
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Aerenita — España
- Aerinita (fibrosa) — España
- Analcima — España
- Analcima — España